I was reading about the history of cable internet and I'm interested in a simple model of full-duplex communications across a single coaxial cable. My first attempt is simply a transmission line with a voltage source at either end.
Either party can send a signal using their voltage source and receive a signal by listening to the voltage across the coax line (voltage detector not shown). This model cannot be right, because what if the left-hand party decides to send a constant 0 signal while the right-hand party wants to send a constant sine wave simultaneously? The left-hand party necessarily shorts his side of the coax which will ruin any ability to detect the sine wave.
They send a signal by driving Vout and detect the signal by reading Vin. The two resistors have very high resistance values. How accurate is my model? Would something like this basically work for full-duplex communication?